Several explosions were heard this morning at Kabul's Marshal Fahim National Defense University.
Reports said the military academy was under attack, but there's no confirmation yet.
Locals said the explosions began at 5am local time and continued for an hour. Smaller blasts could be heard at longer gaps.
In October, 15 cadets were killed in a blast outside this academy.
Kabul military academy reportedly under attack
Gunmen involved in today's attack eliminated: Reports
BBC reports the president's spokesperson has confirmed an attack, and the terrorists weren't able to go past the first gate.
Meanwhile, Reuters quotes police as saying there was an "incident" inside the site, and that there was no clarity on whether it was an attack.
Some reports said the gunmen involved have been neutralized.
Two deadly attacks in the last weeks
This comes a week after 100 people were killed when an ambulance packed with explosives blew up.
The Taliban said it was behind both attacks. The Islamic State too has claimed responsibility for recent attacks in the Afghan capital.